Dicyclopentadiene resin-containing molded article and method for producing the same

Abstract

To provide a molding containing a dicyclopentadiene resin which can satisfy various properties.MEANS FOR SOLVING THE PROBLEM: The present invention relates to a molding containing a dicyclopentadiene resin. The molding has a first phase containing the dicyclopentadiene resin and a hollow particle-like filler.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This specification relates to molded articles containing dicyclopentadiene resins. [Background technology]

[0002] Dicyclopentadiene resins are known to have an excellent balance between strength and hardness. For example, Patent Document 1 discloses a molded article using a dicyclopentadiene resin. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-273796 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, compared to other engineering plastics, dicyclopentadiene resins had the characteristic of being difficult to adjust to properties suitable for the application of molded articles.

[0005] This specification provides molded articles using dicyclopentadiene resins that can satisfy various properties, and methods for producing the same. [Means for solving the problem]

[0006] The present inventors investigated suitable configurations for satisfying various properties using dicyclopentadiene resins and found that by incorporating a phase containing dicyclopentadiene resin and hollow particulate filler, it becomes easier to control properties such as strength, specific gravity, and toughness of the molded article, and optimization of properties becomes possible, thus completing the present invention. Based on these findings, the following means are provided according to this specification.

[0007] [1] A molded article containing a dicyclopentadiene-based resin, comprising a first phase containing a dicyclopentadiene-based resin and a hollow particulate filler. A molded article comprising a first phase containing a dicyclopentadiene-based resin and a hollow particulate filler. [2] The molded article according to [1], wherein the hollow particulate filler contains soft hollow particles. [3] The molded article according to [1] or [2], wherein the first phase further contains a non-hollow particulate filler. [4] The molded article according to any one of [1] to [3], wherein the first phase further contains a fibrous filler. [5] The molded article according to [4], wherein the fibrous filler is a mixture of a large number of fibers that can be separated and dispersed from each other or a sheet body in which a large number of fibers are braided, woven or entangled. [6] A molded article according to any one of [1] to [5], comprising a layer composed of a second phase containing a dicyclopentadiene-based resin and a non-hollow particulate filler, laminated directly or through another layer on the layer composed of the first phase. [7] The molded article according to any one of [1] to [6], further comprising a third phase containing a dicyclopentadiene-based resin and no filler. [8] The molded article according to any one of [1] to [7], having a specific gravity of 0.4 or more and 1.0 or less. [9] A step of forming a precursor, which is at least a part of a molded article to be obtained, using a curable composition containing a monomer component containing a dicyclopentadiene-based monomer, a polymerization catalyst for ring-opening polymerization of the dicyclopentadiene-based monomer, and a hollow particulate filler; A phase formation step of heating the precursor to polymerize the dicyclopentadiene-based monomer to form a phase containing a dicyclopentadiene-based resin and a hollow particulate filler. A manufacturing method comprising the above steps.

[10] The manufacturing method according to [9], wherein the precursor formation step is a step of spray-coating the curable composition on the sheet-like body of the fibrous filler on the surface of a workpiece to be coated.

[11] A curable composition comprising a monomer composition containing a dicyclopentadiene-based monomer, a polymerization catalyst for ring-opening polymerization of the dicyclopentadiene-based monomer, and a hollow particulate filler.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, a molded body disclosed in the present specification (hereinafter, also simply referred to as the present molded body), a manufacturing method thereof (hereinafter, also simply referred to as the present manufacturing method), etc. will be described.

[0009] (First Phase) The molded body disclosed in the present specification includes a first phase containing a dicyclopentadiene-based resin and a hollow particulate filler. By providing such a first phase, it is possible to contribute to properties such as the specific gravity, strength, and toughness of the molded body.

[0010] (Dicyclopentadiene-Based Resin) The present molded body is a molded body containing a dicyclopentadiene-based resin. Here, the dicyclopentadiene-based resin is a resin polymerized using a monomer composition containing at least a dicyclopentadiene-based monomer, and examples thereof include a homopolymer or copolymer of a dicyclopentadiene-based monomer. The dicyclopentadiene-based resin contains structural units derived from dicyclopentadiene-based monomers, structural units derived from other cyclic olefin-based monomers, and the like. The dicyclopentadiene-based resin is advantageous because it has high strength, high toughness, heat resistance, and light weight, and because the curable composition containing the monomer and curing agent before curing has an extremely low viscosity and also has high compatibility with highly polar fillers. [[ID=二十一]]

[0011] [[ID=二十二]] The dicyclopentadiene-based monomer is dicyclopentadiene or a tricyclic compound in which a part of the hydrogen in its structure is substituted with a substituent. The dicyclopentadiene-based monomer may have substituents such as an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or a butyl group; an alkenyl group having 2 to 5 carbon atoms, such as a vinyl group; an alkylidene group having 1 to 5 carbon atoms, such as an ethylidene group; an aryl group having 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, or a naphthyl group. Furthermore, these monomers can have polar groups such as a carboxyl group, an acid anhydride, a hydroxyl group, an ester group (-C(O)O-), an ether group (-O-), an epoxy group, a cyano group, or a halogen atom as substituents. By using such monomers containing polar groups, the compatibility with components having polar groups can be enhanced.

[0012] Specific examples of the dicyclopentadiene-based monomer include non-polar dicyclopentadienes such as dicyclopentadiene, 2-methyldicyclopentadiene, 2,3-dimethyldicyclopentadiene, 2,3-dihydroxydicyclopentadiene, dicyclopentadiene monoepoxide, vinyl norbornene, and 5-ethylidene norbornene.

[0013] The cyclic olefin-based monomers other than the dicyclopentadiene-based monomers that can constitute the dicyclopentadiene-based resin are not particularly limited. For example example example, tricyclopentadiene, pentacyclo[6.5.1.1 3,6 .0 2,7 .0 9,13 pentadeca-4,10-diene, pentacyclo[9.2.1.1 4,7 .0 2,10 .0 3,8 pentadeca-5,12-diene, and hexacyclo[6.6.1.1 3,6 .1 10,13 .0 2,7 .0 9,14 heptadeca-4-ene and other non-polar cyclic olefins having five or more rings; and tetracyclo[6.2.1.1 3,6 .0 2,7] Dodeca-4-ene, 9-methyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-ethyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-cyclohexyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-cyclopentyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-methylenetetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-ethylidenetetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-vinyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-propenyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-cyclohexenyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene, 9-cyclopentenyltetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-4-ene and 9-phenyltetracyclo[6.2.1.1 3,6 .0 2,7 Examples include nonpolar tetracyclododecenes such as dodeca-4-ene; and others.

[0014] Furthermore, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-9-ene-4-carboxylate methyl, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-9-ene-4-methanol, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-9-ene-4-carboxylic acid, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Dodeca-9-ene-4,5-dicarboxylic acid, tetracyclo[6.2.1.13,6 .0 2,7 Examples of polar norbornenes include dodeca-9-en-4,5-dicarboxylic acid anhydride, methyl 5-norbornene-2-carboxylate, methyl 2-methyl-5-norbornene-2-carboxylate, 5-norbornene-2-yl acetate, 5-norbornene-2-methanol, 5-norbornene-2-ol, 5-norbornene-2-carbonitride, 2-acetyl-5-norbornene, and 7-oxa-2-norbornene.

[0015] From the viewpoint of compatibility and other factors, the cyclic olefin monomers used in the dicyclopentadiene-based resin of this molded product are non-polar dicyclopentadienes and non-polar cyclic olefins.

[0016] Dicyclopentadiene resins may further contain components and units derived from other cyclic diene monomers. Examples include, but are not limited to, nonpolar tetracyclododecenes, nonpolar norbornenes, norbornene monomers containing polar groups, and monocyclic olefins.

[0017] The amount of dicyclopentadiene monomers relative to the total amount of cyclic olefin monomers is, for example, 55% by mass or more and 95% by mass or less, for example, 60% by mass or more and 90% by mass or less, for example, 70% by mass or more and 90% by mass or less, for example, 80% by mass or more and 90% by mass or less. Furthermore, when the monomer composition contains cyclic olefin monomers other than dicyclopentadiene monomers, the amount of these monomers relative to the total amount is, for example, 5% by mass or more and 45% by mass or less, for example, 8% by mass or more and 30% by mass or less, for example, 10% by mass or more and 20% by mass or less.

[0018] A dicyclopentadiene resin can be obtained by polymerizing and curing a curable composition containing a cyclic diene monomer including a dicyclopentadiene monomer and possibly other monomers, along with a polymerization catalyst capable of ring-opening polymerization of the dicyclopentadiene monomer, under predetermined temperature conditions.

[0019] Known metathesis catalysts can be used as such polymerization catalysts. Examples of metathesis catalysts include complexes in which multiple ions, atoms, polyatomic ions, and / or compounds are bonded to a transition metal atom. Atoms from groups 5, 6, and 8 (long-period periodic table, hereinafter the same) are used as transition metal atoms. The atoms of each group are not particularly limited, but preferred group 5 atoms are tantalum, preferred group 6 atoms are molybdenum and tungsten, and preferred group 8 atoms are ruthenium and osmium. For example, a metathesis polymerization catalyst is a complex of ruthenium and osmium from group 8, and another example is a ruthenium carbene complex. Ruthenium carbene complexes exhibit excellent catalytic activity during bulk polymerization.

[0020] Specific examples of ruthenium carbene complexes include those disclosed in Japanese Patent Publication No. 2014-218595, as well as commercially available ones. Typically, these include benzylidene (1,3-dimethyl-4-imidazolidin-2-ylidene)(tricyclohexylphosphine)ruthenium dichloride, benzylidene (1,3-dimethyl-4,5-dibromo-4-imidazoline-2-ylidene)(tricyclohexylphosphine)ruthenium dichloride, (1,3-dimethyl-4-imidazoline-2-ylidene)(3-phenyl-1H-indene-1-ylidene)(tricyclohexylphosphine)ruthenium dichloride, and (1,3-dimethyl-4-imidazoline-2-ylidene)(3-phenyl-1H-indene-1-ylidene)(tricyclohexylphosphine)ruthenium dichloride. Zolidine-2-ylidene)(3-methyl-2-butene-1-ylidene)(tricyclopentylphosphine)ruthenium dichloride, benzylidene (1,3-dimethyl-octahydrobenzimidazole-2-ylidene)(tricyclohexylphosphine)ruthenium dichloride, benzylidene [1,3-di(1-phenylethyl)-4-imidazoline-2-ylidene](tricyclohexylphosphine)ruthenium dichloride, benzylidene (1,3-dimethyl-2,3-dihydrobenzimidazole-2- Iridene (tricyclohexylphosphine)ruthenium dichloride, benzylidene (tricyclohexylphosphine) (1,3,4-triphenyl-2,3,4,5-tetrahydro-1H-1,2,4-triazole-5-ylidene)ruthenium dichloride, (1,3-diisopropylhexahydropyrimidine-2-ylidene) (ethoxymethylene) (tricyclohexylphosphine)ruthenium dichloride, benzylidene (1,3-dimesityl-4-imidazolidinedine-2-ylidene)pyridineruthenium dichloride Lorid, (1,3-Dimethyl-4-Imidazolidine-2-Ilidene)(2-Phenylethylidene)(Tricyclohexylphosphine)Ruthenium Dichloride, (1,3-Dimethyl-4-Imidazolin-2-Ilidene)(2-Phenylethylidene)(Tricyclohexylphosphine)Ruthenium Dichloride, (1,3-Dimethyl-4,5-Dibromo-4-Imidazolin-2-Ilidene)[(Phenylthio)methylene](Tricyclohexylphosphine)Ruthenium Dichloride and (1,3-Dimethyl-4,Ruthenium complex compounds, such as 5-dibromo-4-imidazoline-2-ylidene)(2-pyrrolidone-1-ylmethylene)(tricyclohexylphosphine)ruthenium dichloride, in which one heteroatom-containing carbene compound and one neutral electron-donating compound are bonded;

[0021] Ruthenium complex compounds in which two neutral electron-donating compounds are bonded, such as benzylidenebis(tricyclohexylphosphine)ruthenium dichloride and (3-methyl-2-butene-1-ylidene)bis(tricyclopentylphosphine)ruthenium dichloride;

[0022] Ruthenium complex compounds in which two heteroatom-containing carbene compounds are bonded, such as benzylidenebis(1,3-dicyclohexyl-4-imidazolidin-2-ylidene)ruthenium dichloride and benzylidenebis(1,3-diisopropyl-4-imidazoline-2-ylidene)ruthenium dichloride;

[0023] Other examples include (1,3-dimethyl-4-imidazolidin-2-ylidene)(phenylvinylidene)(tricyclohexylphosphine)ruthenium dichloride, (t-butylvinylidene)(1,3-diisopropyl-4-imidazoline-2-ylidene)(tricyclopentylphosphine)ruthenium dichloride and bis(1,3-dicyclohexyl-4-imidazoline-2-ylidene)phenylvinylideneruthenium dichloride.

[0024] Furthermore, compounds having catalytic activity equivalent to or superior to the above-mentioned compounds can be used as appropriate.

[0025] The amount of metathesis polymerization catalyst used in this curable composition is not particularly limited, but for example, the molar ratio of metal atoms to cyclic olefin monomers in the metathesis polymerization catalyst is in the range of (1:2,000) to (1:2,000,000), preferably (1:5,000) to (1:1,000,000), and more preferably (1:10,000) to (1:500,000). By having the amount of metathesis polymerization catalyst within the above range, a suitable polymerization reaction rate and reaction rate can be ensured.

[0026] (Hollow particulate filler) The first phase contains a hollow particulate filler, which can contribute to reducing the specific gravity and improving the strength of the molded article. The hollow particulate filler is not particularly limited as long as it has a hollow internal structure, and known particles can be used. Examples include porous particles and outer-shell particles that form a hollow part (air layer) inside. The hollow internal structure is not particularly limited, but may be an independent internal structure that does not communicate with the outside, or an internal structure that communicates with the outside. Typically, it has an independent internal structure that does not communicate with the outside, and holds a gas, for example, derived from a blowing agent, inside.

[0027] Because hollow particulate fillers have a low specific gravity due to their hollow structure, they can be easily dispersed in dicyclopentadiene-based monomer components, which have excellent fluidity, allowing for the easy production of a curable composition with a uniform dispersion. Furthermore, this dispersion state can be maintained even during film formation.

[0028] The outer shell material for the hollow particulate filler is not particularly limited to ceramics, glass, polymers, etc., but polymers are preferred because they contribute to lightness and the plasticity of the molded product. Among these, thermoplastic resins are preferred from the viewpoint of elasticity, stretchability, and gas barrier properties when softened by heating. The thermoplastic resin is not particularly limited, but for example, a (meth)acrylonitrile-based polymer that has (meth)acrylonitrile as the main component and may contain alkyl (meth)acrylate is an example. By using such an outer shell material for the hollow particulate filler, fracture resistance and flexural resistance can be easily imparted to the dicyclopentadiene-based resin.

[0029] The individual particles of the hollow particulate filler are generally spherical. The average particle diameter of the hollow particles is not particularly limited, but can be, for example, 10 μm to 500 μm, 20 μm to 100 μm, 30 μm to 80 μm, or 40 μm to 60 μm. The average particle diameter of the hollow particles can be measured using a laser diffraction scattering particle size distribution analyzer (Microtrac ASVR, manufactured by Nikkiso Co., Ltd.), and the D50 value can be used as the average particle diameter.

[0030] Furthermore, as hollow particulate fillers, for example, those with a true specific gravity of 0.020 to 0.050, 0.020 to 0.040, or 0.025 to 0.035 can be used. Within this range, excellent uniform dispersibility is achieved in dicyclopentadiene monomers and the like. The true specific gravity can be measured by immersion method (Archimedes method) using isopropyl alcohol in an atmosphere with an ambient temperature of 25°C and a relative humidity of 50%.

[0031] The content of the hollow particulate filler in the first phase is not particularly limited, but for example, it is 0.5% by mass or more and 20% by mass of the total amount of dicyclopentadiene resin in the first phase (hereinafter the same applies to the content of the filler), or for example, 1% by mass or more and 10% by mass, or for example, 1% by mass or more and 8% by mass, or for example, 1% by mass or more and 6% by mass, or for example, 1% by mass or more and 4% by mass, or for example, 1% by mass or more and 3% by mass.

[0032] (Non-hollow particulate filler) The first phase may further contain a non-hollow particulate filler. The non-hollow particulate filler is not particularly limited as long as it is a solid particle that does not have a hollow structure inside, but does not include particles with an aspect ratio of 10 or more, such as fibrous fillers. Such solid particles are not particularly limited, and various known fillers such as ceramics, glass, inorganic compounds, and polymers can be used. For example, inorganic particle fillers such as calcium carbonate and silicon dioxide can be used. The non-hollow particulate filler may be spherical, for example, or it may have an irregular shape.

[0033] The non-hollow particulate filler is well dispersed and retained in the dicyclopentadiene resin, and the hollow particulate filler is stably retained in the first phase of the dicyclopentadiene resin. As a result, the hollow particulate filler can be retained in the first phase with excellent dispersibility.

[0034] The average particle size of the non-hollow particulate filler is not particularly limited, but can be, for example, 0.1 μm to 500 μm, 1 μm to 300 μm, 0.5 μm to 200 μm, or 1 μm to 100 μm. The average particle size of non-hollow particles can be measured using a laser diffraction scattering particle size distribution analyzer (Microtrac ASVR, manufactured by Nikkiso Co., Ltd.), and the D50 value can be used as the average particle size.

[0035] The content of the non-hollow particulate filler in the first phase is not particularly limited, but for example, it may be 0.5% to 30% by mass of the dicyclopentadiene resin, or for example, 1% to 30% by mass, or for example, 2% to 20% by mass, or for example, 2% to 10% by mass, or for example, 3% to 7% by mass.

[0036] (Fiber-like filler) The first phase may contain a fibrous filler. The fibrous filler is not particularly limited, and various known fibrous fillers can be used. For example, a mixture of many fibers that can be separated and dispersed from one another can be used. In the case of such a filler, the fibers are generally between 10 μm and several mm in size, and various fiber mixtures such as glass, ceramic, plastic, and metal fibers can be used. In such fiber mixtures, some fibers may be aggregated due to entanglement or the like. By using such a fibrous filler, non-directional strength can be imparted to the second layer. Furthermore, depending on the specific gravity of the fibrous filler used, the specific gravity of the second layer can be reduced.

[0037] The content of such dispersible fibrous fillers in the first phase is not particularly limited. For example, it can be used in ranges such as 1% to 80% by mass, 2% to 70% by mass, 5% to 60% by mass, or 10% to 50% by mass of the total mass of the dicyclopentadiene resin.

[0038] Furthermore, as the fibrous filler, a sheet-like or net-like material can be used in which fibers are knitted, woven, or entangled. The sheet-like filler is made by knitting, weaving, or entangling filament yarns or spun yarns and then needle punching them as needed to form a sheet-like material. The net-like material is made by crossing filament yarns or spun yarns and partially fixing them to form a mesh. By using such a sheet-like or net-like material, the elasticity as well as the strength along the surface of the sheet-like or net-like material can be improved in the first phase. In addition, the resistance to external forces that would cause the surface of the sheet-like or net-like material to break or bend can be improved.

[0039] Examples of sheet-like materials include bundles of glass filaments, which are available as roving cloth or glass cloth, that have been woven together. The curable composition of dicyclopentadiene resin can effectively impregnate such sheet-like materials, suppressing or avoiding the formation of air bubbles, and penetrate into the interior of the woven structure, thus becoming a first phase with excellent integrity for the sheet-like material.

[0040] Such sheet-like or net-like materials may comprise one or more layers in the first phase.

[0041] The first phase may preferably include a non-hollow particulate filler in addition to a hollow particulate filler, and may also preferably include a sheet-like or net-like filler in addition to these.

[0042] Furthermore, based on the above, the curable composition for forming the first phase may include a monomer composition containing a dicyclopentadiene monomer, a metathesis polymerization catalyst, and a hollow particulate filler. It may also include a non-hollow particulate filler.

[0043] (Second phase) The molded article may further comprise a second phase containing a dicyclopentadiene resin and a non-hollow particulate filler. By providing such a second phase, an outer surface can be provided that is covered with surface irregularities that may be present in the first phase due to the hollow particulate filler. As the non-hollow particulate filler, particles of the embodiments already described can be used.

[0044] The content of the non-hollow particulate filler in the second phase is not particularly limited, but for example, it may be 0.5% to 30% by mass of the dicyclopentadiene resin, or for example, 1% to 30% by mass, or for example, 2% to 20% by mass, or for example, 2% to 10% by mass, or for example, 3% to 7% by mass.

[0045] (The third phase) The molded article may further comprise a third phase containing a dicyclopentadiene resin but without fillers. By including such a third phase, the molded article can contribute to improving the properties of the dicyclopentadiene resin, such as strength, low-temperature impact resistance, and heat resistance. By providing such a layer on the surface, surface strength, low-temperature impact resistance, and heat resistance can be improved. The third phase is a layer that does not contain any of the hollow particulate fillers, fibrous fillers, or non-hollow particulate fillers described above.

[0046] (The fourth phase) The molded article may further comprise a fourth phase containing a dicyclopentadiene resin and a rubber-based filler. Because it contains a rubber component, it can contribute to improving the tensile strength, fracture resistance, and toughness of the molded article. The fourth layer may also contain, in addition to the dicyclopentadiene resin and rubber component, one or more of the hollow particulate fillers, non-hollow particulate fillers, and fibrous fillers described above, but it does not have to contain all of these.

[0047] The rubber-based filler is not particularly limited, and known rubber particles can be used. Typically, various rubber particles such as styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), isoprene rubber (IR), EPM / EPDM (ethylene propylene rubber), acrylonitrile-butadiene rubber or nitrile rubber (NBR), silicone rubber (Q), fluororubber (FKM), acrylic rubber (ACM, ANM), urethane rubber, polysulfide rubber, and epichlorohydrin rubber can be used as appropriate.

[0048] The content of the rubber-based filler in this layer is not particularly limited, but for example, it may be 0.5% to 40% by mass of dicyclopentadiene resin, or for example, 1% to 30% by mass, or for example, 2% to 25% by mass, etc.

[0049] (Structure of this molded body) The present molded article is a molded article comprising at least a first phase, and the form occupied by the first phase in the present molded article is not particularly limited. Preferably, the present molded article is a laminate that comprises one or more layers of the first phase. In addition to the first phase, a laminate is also preferred in which one or more phases selected from the group consisting of a second phase, a third phase, and a fourth phase that constitute the present molded article are each provided as layers. By combining the first phase and, if necessary, one or more of the second, third, and fourth phases to form a laminate, it is possible to impart strength, hardness, elasticity, specific gravity, etc., that are suitable for various applications.

[0050] The molded body may comprise one or more layers of the first phase. Multiple layers of the first phase may be directly laminated. The second phase may also comprise one or more layers as needed. The second phase is laminated to cover at least a portion, for example, the entire surface of a unit consisting of one first phase or multiple layers of the first phase. The second phase may also be provided on the outermost surface of such a laminate, i.e., on one or both of the outermost layers along the lamination direction of the laminate.

[0051] The third and fourth phases may each consist of one or more layers, as needed. The locations where these layers are stacked are not particularly limited. These phases can be used as intermediate phases or as surface layers as appropriate.

[0052] The specific gravity of the molded article is not particularly limited, but for example, it is between 0.4 and 1.0. Because the molded article contains a first phase, it can exhibit excellent strength, toughness, and heat resistance despite having a specific gravity of 1.0 or less. Furthermore, by containing a second phase and a third phase, it can exhibit strength, toughness, elasticity, damping, etc., based on the fibrous filler.

[0053] (Method of manufacturing this molded product) A method for producing a molded article disclosed herein may include the steps of forming a precursor which is at least a part of the molded article to be obtained using a curable composition comprising a monomer component containing a dicyclopentadiene monomer, a polymerization catalyst for ring-opening polymerization of the dicyclopentadiene monomer, and a hollow particulate filler; and a phase-forming step of heating the precursor and polymerizing the dicyclopentadiene monomer to form a phase comprising a dicyclopentadiene resin and a hollow particulate filler.

[0054] This manufacturing method makes it possible to produce a molded article (laminated article) having a layer in which hollow particulate filler is held in an excellent dispersed state within a dicyclopentadiene resin. Therefore, it is possible to produce a molded article of dicyclopentadiene resin that has excellent elasticity and tensile properties in addition to lightness and strength.

[0055] Specifically, for example, the precursor formation step can be a coating film formation step in which a curable composition comprising a monomer composition containing a cyclopentadiene monomer, a polymerization catalyst for ring-opening polymerization of the monomer composition containing the dicyclopentadiene monomer, a hollow particulate filler, and a non-hollow particulate filler is applied to a workpiece by spray coating or the like to form a coating film. Furthermore, the phase formation step can be a layer formation step in which the coating film is heated and a layer containing a dicyclopentadiene resin and a hollow particulate filler is formed by mass polymerization or the like.

[0056] In this manufacturing method, the coating film formation step can be a step of spray-painting a curable composition onto a fibrous sheet of a workpiece that has a sheet of fibrous filler on its surface. By doing so, the dicyclopentadiene resin can sufficiently penetrate the sheet, suppressing or avoiding the formation of air bubbles, and a composite layer can be formed in which hollow particulate filler and non-hollow particulate filler are well dispersed.

[0057] (Curable composition for manufacturing fiber-reinforced molded articles) This curable composition may include a monomer composition containing a dicyclopentadiene monomer, a polymerization catalyst for ring-opening polymerization of the dicyclopentadiene monomer, and a hollow particulate filler. Because this curable composition includes a hollow particulate filler, it can improve the lightness and strength of dicyclopentadiene resins. This curable composition may also appropriately include other additives and auxiliary agents that can be included in this type of curable composition, such as antioxidants. [Examples]

[0058] (Preparation of the surface layer) This example describes a method for manufacturing a torso. A torso mold having molded surfaces corresponding to the front and back of the torso was prepared. A mixture of TELENE1800EMS (a monomer composition containing dicyclopentadiene monomers) and TELENE1800CS (a metathesis polymerization catalyst) (both manufactured by RIMTEC) in a mass ratio of 100:3 was applied to the molded surface of the torso mold with a brush. The total amount applied to the torso was 100g. After applying this curable composition, the torso mold was placed in a curing oven at 60°C and held for 30 minutes, then left outside the oven to cool.

[0059] (Preparing the middle class) After cooling, a mixture of TELENE1800MS (a monomer composition containing dicyclopene diene monomers, manufactured by RIMTEC), resin balloons (manufactured by Matsumoto Oil & Fat Co., Ltd., shell composition: acrylonitrile resin, average particle size: 40-60 μm, true specific gravity 0.025-0.035), and TELENE1800CS (metathesis polymerization catalyst), blended in a mass ratio of 100:15:3, was sprayed onto the surface of the cured film using a lysine gun at a blending ratio of 100:15:3 to form a coating film. The total spraying amount was 1400 g for the entire torso. The torso mold with this curable composition applied was placed in a 60°C curing oven and held for 30 minutes, then left outside the oven to cool.

[0060] (Preparing the reverse side) After cooling, a curable composition similar to that used for the surface layer was prepared and applied to the surface of the film that had hardened inside the torso mold using a brush. The total amount applied to the torso was 150g. The torso mold with this curable composition applied was placed in a 60°C curing oven and held for 30 minutes, after which it was left outside the oven to cool.

[0061] After forming the front and back portions of the torso within the torso mold, a curable composition similar to that used for the intermediate layer was applied to the joint surface between the two portions. The torso mold was then clamped with bolts and cured in a 60°C curing oven for 30 minutes. After cooling, the mold was demolded, and burrs were removed from the joint. The torso was then placed in a 110°C curing oven, and after the product temperature exceeded 100°C, it was cured for another 10 minutes. It was then left to cool outside the oven.

[0062] The resulting torso was lightweight, as it consisted of walls with an average thickness of 4mm, yet possessed sufficient strength.

[0063] The specific examples of the technologies disclosed in this specification have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples described above. The technical elements described in this specification exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technologies exemplified in this specification can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness.

Claims

1. A method for producing a molded article containing a dicyclopentadiene resin, The invention comprises a first curable composition comprising a monomer component containing a dicyclopentadiene monomer, a polymerization catalyst for ring-opening polymerization of the dicyclopentadiene monomer, and a hollow particulate filler having an outer shell containing a thermoplastic resin, a true specific gravity of 0.020 to 0.050, and a D50 value of 40 μm to 60 μm as determined by laser diffraction scattering particle size distribution measurement, and a first layer formation step comprising applying the first curable composition, which does not contain a crosslinking agent, by spray coating, and forming a first layer consisting of a first phase containing a dicyclopentadiene resin by ring-opening polymerization, Prior to the first layer formation step, a third curable composition is supplied to the portion that will become the surface layer of the first layer, comprising a monomer component containing a dicyclopentadiene monomer and a polymerization catalyst for ring-opening polymerization of the dicyclopentadiene monomer, and not containing a crosslinking agent or filler, thereby forming the surface layer consisting of a third phase containing a dicyclopentadiene resin by ring-opening polymerization. The first layer formation step is a manufacturing method comprising spray coating the surface layer with the first curable composition.

2. The manufacturing method according to claim 1, further comprising an additional layer formation step, after the first layer formation step, of supplying the third curable composition to the portion that will be the back surface of the first layer to form a back surface layer consisting of the third phase by ring-opening polymerization.

3. The manufacturing method according to claim 1, wherein the first layer further contains a non-hollow particulate filler.

4. The manufacturing method according to claim 1, wherein the first layer further contains a fibrous filler.

5. The manufacturing method according to claim 4, wherein the fibrous filler is a mixture of a large number of fibers that can be separated and dispersed from each other, or a sheet-like body in which a large number of fibers are knitted, woven, or entangled.

6. The manufacturing method according to claim 1, wherein the specific gravity of the molded article is 0.4 or more and 1.0 or less.

7. The first layer comprises a sheet-like fibrous filler, The manufacturing method according to claim 1, wherein the first layer forming step includes spray coating the sheet-like body with the first curable composition.